1. Field of Invention
This invention relates generally to improvements in kayak construction, specifically sit-on-top kayaks.
2. Description of Prior Art
Prior to issuance of U.S. Pat. No. 6,745,716 to the present inventor there existed a need for a kayak which provides reconfiguration for varying paddling needs and situations via a modular kayak design. U.S. Pat. No. 6,745,716 teaches of a kayak with central hull voids and removable central hulls. However, the need exists for a self bailing sit-on-top kayak not fully disclosed by the present inventor in U.S. Pat. No. 6,745,716. Reading on the claims of U.S. Pat. No. 6,745,716, one can see that an element of that invention, the removable cockpit is an integral part of the previous invention, and is therefore required to complete the invention in a practical and useful manner. The removable cockpit of U.S. Pat. No. 6,745,716 is eliminated herein via a new design and manufacturing process which allows for a self bailing design of sit-on-top kayak by introducing an elevated centrally located void and having drain holes empty into the void above the waterline within a non-removable cockpit area.
The process of manufacturing rotationally-molded polyethylene sit-on-top kayaks is generally discussed in U.S. Pat. Nos. 5,397,525 5,964,177 6,152,063 and 6,178,912 issued to Timothy A. Niemier. However, Niemier does not allude to or teach of using centrally located central hull voids in a manner to facilitate modular storage and or insertion of modules for changing the running surface of a sit-on-top kayak. Niemier does teach of vertical scupper holes as are common to most sit-on-top kayak designs. Originally used to add stiffness to the upper portion or deck of the sit-on-top kayak separating it from the bottom, thus preventing collapse, and also to allow for water to exit through the scupper holes. Depending upon the amount of weight in the kayak, the top of scupper holes are above or at the waterline, but when over-laden can be below the waterline allowing an inflow of water into the paddler seating area recess. Scuppers are designed as a vertical pipe to be located at the lowest point in the cockpit or foot rest area during normal usage. It has historically been problematic to insure a properly formed scupper via rotational molding due to manner in which the parting line of traditional rotational molds mate within a small area to create the scupper. The interior of the scupper void, where the top and bottom halves of the molds from which they are formed meet, is the most common area of leakage in sit-on-top kayak hulls. There is normally insufficient room for clamps on the mold to insure a tight fit between the mold halves, resulting in mold leaks and possible holes within the seam of the scupper. Due to the increased probability of a leaking parting line within the scupper area, manufacturing costs are increased due to scrap, re-work, and returns of kayaks from customers who found them to leak. Niemier does not teach of a hull void which extends from the bottom of the craft to the proximity of the gunwales, nor does he describe the method by which such a void can be manufactured to allow for use as a thigh brace and storage receptacle, as well as a means by which the running surface of the kayak can be altered. Nor does Niemier teach of a modular design or use of a central hull void into which water from the cockpit can drain centrally and above the normal laden waterline. In U.S. Pat. No. 5,417,179, Niemier teaches of a bracing structure located in the central area of the sit-on-top kayak cockpit which can be removed. He does not teach of an elevated area unitarily formed within the kayak cockpit which can be used as a brace member. Lastly, no prior art has been found which teaches of such or suggests such in combination or in part.
In U.S. Pat. No. 5,476,055 issued to Hackett, et al. Dec. 19, 1995, Hackett teaches of an underwater viewing apparatus inserted within a boardlike craft which allows for water to drain around the viewing apparatus. Hacket does not teach of a centrally located elevated void or of such a void within a cockpit or of a void into which water may drain from a cockpit, but rather a method whereby water may drain around the edges of his viewing device to facilitate viewing. Also, as taught by Hackett, a viewing unit must be in place to define his invention. It is clear that the design and described invention by Hackett was not intended nor did teach of the use of an elevated hull void centrally located within a kayak and elevated within a cockpit or for use in a modular manner, or for use as a central drainage system.
In the ship building industry may be found numerous prior art references of ship hull designs which allow for voids in the center of ships as can be seen in U.S. Pat. No. 6,220,194 issued to Kjersem on Apr. 24, 2001. In his patent, Kjersem describes the use of hull voids for the stabilization of ships and to allow for use as access to the water below confined within the center of the ship.
U.S. Pat. No. 6,022,249 Ketterman describes a novel propulsion means for a kayak whereby a void in the rotomolded hull accommodates a propulsion device. The void is shown to act as a self bailing scupper of a size and shape to accept insertion of a peddle device to propel the kayak. While Ketterman does not teach of the manufacture of a kayak with a void in the hull, his device is dependent upon such to function as described. However Ketterman's device does not teach of a hull void which serves as a receptacle for storage or flotation, nor does it teach of a hull void which extends from the bottom of the craft to the proximity of the gunwales, nor does he describe the method by which such a void can be manufactured to allow for use in a modular fashion or use as an elevated cockpit central drainage system.
Masters teaches of a cockpit drain system whereby water is drained from the lower portion of a kayak seating area through ports in the sides of the kayak in U.S. Pat. No. 4,589,365. Such an arrangement as taught by Masters has proven problematic in low free-board vessels such as canoes and kayak in that it allows as much or more water in as out, due to the low nature of the crafts gunwales and from wave action.
It is not uncommon for kayak dealers as well as manufacturers to supply corks and plugs for insertion into scupper holes to disallow water entry via traditional scuppers. As a standard practice a plug is supplied with each of Ketterman's kayaks as is the practice with most leading kayak manufacturers, which further illustrates the problematic nature of traditional scupping holes in sit-on-top kayaks.
From the foregoing, it should be clear that one primary object of the present invention is to provide an improved self bailing sit-on-top kayaks with central hull voids which allow for modular storage, hull reconfiguration, propulsion means, a new method of bailing a sit-on-top kayak as well elimination of traditional scuppers as a means of stiffening the upper deck, also eliminated is the requirement of a module to be inserted in order for the kayak to provide for seating while remaining self bailing.
Prior art is replete with various boat, canoe and kayak designs and various forms of manufacture and add-ons. In the crowded art, small changes and combinations of existing articles of manufacture can yield unexpected results and improvements to human powered watercraft not obvious when viewed as individual parts and components. The claims contained herein are in no small part a minor change to or reliance upon the prior art of others and are a discovery born of this inventor's previous discoveries and research.